Canadian cancer screening disparities: a recent historical perspective.

Across Canada, introduction of the Pap test for cervical cancer screening, followed by mammography for breast cancer screening and, more recently, the fecal occult blood test for colorectal cancer screening, has contributed to a reduction in cancer mortality. However, another contribution of screening has been disparities in cancer mortality between certain populations. Here, we explore the disparities associated with breast and cervical cancer screening and preliminary data concerning disparities in colorectal cancer screening. Although some disparities in screening utilization have been successfully reduced over time (for example, mammography and Pap test screening in rural and remote populations), screening utilization data for other populations (for example, low-income groups) clearly indicate that disparities have existed and continue to exist across Canada. Organized screening programs in Canada have been able to successfully engage 80% of women for regular cervical cancer screening and 70% of women for regular mammography screening, but of the women who remain to be reached or engaged in regular screening, those with the least resources, those who are the most isolated, and those who are least culturally integrated into Canadian society as a whole are over-represented. Population differences are also observed for utilization of colorectal cancer screening services. The research literature on interventions to promote screening utilization provides some evidence about what can be done to increase participation in organized screening by vulnerable populations. Adaption and adoption of evidence-based screening promotion interventions can increase the utilization of available screening services by populations that have experienced the greatest burden of disease with the least access to screening services.